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Study of Starch Granules Swelling by the Blue Dextran Method and by Microscopy
Author(s) -
Contreras López Elizabeth,
Rolée Arnaud,
Le Meste Martine
Publication year - 2004
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.200400284
Subject(s) - swelling , starch , dextran , corn starch , optical microscope , materials science , swelling capacity , microscopy , phase (matter) , chemistry , food science , composite material , chromatography , scanning electron microscope , organic chemistry , optics , physics
The evolution of corn and wheat starch granules swelling at different temperatures was determined by two techniques: the blue dextran method (which measures the swelling factor) and by optical (light) microscopy. The graphical results obtained using the blue dextran technique showed curves indicating the swelling of corn and wheat starch dispersions (at 64%, w/w, moisture content) characterized by an initial phase of slight swelling, a second phase of fast swelling and a final phase of maximum swelling. The concentrated solutions (42% and 47%, w/w, moisture content) showed a slight swelling with the increase in temperature. The effect of temperature on the shape of the granules was evaluated by the optical microscopy. The shape of the type A wheat starch granules was deformed at high temperatures. The corn and type B wheat granules had a spherical form. In the case of corn starch, a good correlation ( r 2 = 0.929) was obtained between the results of optical microscopy and blue dextran techniques.